1. Field of the Invention
The present invention relates to an accumulator device, and a method for making the accumulator device for use in air-conditioning systems and particularly for use in the air-conditioning system of an automobile.
2. Description of the Prior Art
The use of accumulators in air-conditioning systems, particularly vehicular air-conditioning systems, is well known. An accumulator is placed downstream of an evaporator, which cools the passenger compartment air as it is passed over and through the evaporator, and therefore takes in partially or completely vaporized refrigerant fluid that usually has a small amount of condensed water and a small amount of lubricating oil necessary to the functioning of the compressor. The partially vaporized refrigerant fluid entering the accumulator, being on the downstream side of the evaporator, is at a relatively low pressure, in the order of 40 psig, and at a raised but relatively low temperature, in the order of 15.6.degree. C. (60.degree. F.) (there being a modest temperature rise through the evaporator of about 5.6.degree. C. (10.degree. F.) The accumulator functions to assure that only vapor refrigerant fluid without any liquid refrigerant fluid passes to the compressor, that this vapor be moisture-free and include a prescribed amount of lubricating oil, and that the oil-laden vapor be free of particulates that might otherwise harm the compressor.
Thus, the known accumulators of the prior art basically accomplish five functions: (i) completely vaporize the refrigerant fluid, (ii) remove all water vapor from the refrigerant fluid, (iii) screen all particulates, (iv) inject a predetermined amount of lubricating oil into the outgoing refrigerant fluid vapor stream, and (v) act as a reservoir for the refrigerant fluid when air-conditioning system demand is low. Typical examples of accumulators accomplishing these functions are shown in U.S. Pat. Nos. 3,798,921; 4,111,005; 4,291,548; 4,496,378 and 5,052,193.
The major challenges in designing such an accumulator are to provide one which is efficient, one which fits well within the environment, in other words, fits within the engine compartment and is easily accessible for maintenance, and one which is inexpensive to manufacture.
Of particular interest with regard to operation efficiency, that is, ensuring only vapor refrigerant fluid is passed to the compressor, and manufacturing cost, is the design and structure of the interior parts of the accumulator. A certain degree of structural rigidity is necessary to warrant life expectancy of the accumulator and to ensure that the interior of the accumulator properly serves the purpose of separating pure vapor from liquid-laden vapor by allowing only the former to pass through to the outlet while the latter is recirculated until it is completely vaporized. In order to meet this objective, the prior art has typically used a baffle member as part of the interior of the accumulator. For example, U.S. Pat. Nos. 4,291,548 and 5,052,193 are directed towards the design of a baffle which is a separate member or component designed to be placed within the system in some convenient manner to enhance the vaporizing process.
Additionally, U.S. Pat. No. 5,075,967 issued to Bottum is directed towards a design for an accumulator having cylindrical casing end caps, an inlet passage, and an outlet passage combined within a standpipe. The inlet passage, outlet passage, and standpipe are constructed essentially of copper and are brazed to the end closures of the cylinder casing resulting in an expensive, weld-filled, heavy and less than efficient design.
U.S. Pat. No. 4,675,971 issued to Masserang shows a method of manufacturing a desiccant assembly for a refrigeration circuit. The method includes cutting a piece of seamless passage stock and friction forming one end of the passage to form an end wall. Refrigerant passages are installed in the container along with other associated components. This is expensive to manufacture and is not concerned with reducing the manufacturing costs associated with designing the interior parts of an accumulator.
As can be seen from the above, there is still a significant need for an accumulator which will accomplish the above-listed functions and which is simplified, more efficient, less costly and easier to manufacture. To this end, it would be preferable to eliminate any or all brazing in the accumulator, to eliminate expensive interior parts such as the aluminum passages, and to provide an accumulator that can be more readily adapted to a variety of environments.